There are numerous mechanisms, including well-known clutch systems that are specifically designed for transmitting torque between machines. Many of these mechanisms and clutch systems have parts that engage, disengage and transmit torque. For various reasons, including the need for reliable transmission of torque at different angular velocities, the prior mechanisms attempt to fix and preserve axial alignment between the machines. Typically, machines achieve this by providing for mechanical engagement between the machines along the axis about which the torque is to be transmitted. In most conventions, this is the Y-axis of the Cartesian coordinate system used in the art of mechanical engineering to parameterize clutch systems and the like.
In these prior art systems, operation commences by actuating one of the two couplers, either the drive or the driven coupler, along the Y-axis. Such axial motion along the Y-axis usually engages gear teeth or other coupling features arranged in the X-Z plane and belonging to the drive and driven couplers. Such solutions are often found in power takeoffs on cars, in which an operator inserts the first coupling into the other coupling along a common axis (axially).
One example of the prior art approach is found in U.S. Pat. No. 3,747,966 to Wilkes, who teaches an agricultural tractor with an externally splined power takeoff shaft, which extends longitudinally from the rear portion. A power transmission shaft having a hollow, internally splined portion at its forward end can be connected to the externally splined power takeoff shaft. Engagement and coupling between these shafts is achieved through actuation along the axis about which torque is transmitted.
Another example of a prior art approach to a torque-transmitting mechanism with a latching apparatus is found in U.S. Pat. No. 7,036,644 to Stevenson. Here the mechanism for engaging a torque supply is embodied by a motor with a torque output, such as a wheel. The teachings identify many mechanisms for linear actuation of the torque-transmitting mechanism along the axis about which torque is to be transmitted.
Still another example is provided by the teachings of Nayak in U.S. Pat. No. 6,318,657, which discloses a mechanism for transmitting torque from a coupling to a tape reel while permitting easy engagement. Here, a tape cartridge is provided with reliable reel lock and motor/reel coupling mechanisms whose functions are both accomplished during a single motion of the cartridge relative to the drive motor. Once again, this is a good example of actuation along the axis around which torque is transmitted.
In fact, the prior art is replete with teachings addressing axial actuation in torque transmission apparatus. For select references teaching standard as well as several non-standard coupling designs in such apparatus, the reader is referred to U.S. Pat. No. 4,289,414 to Recker, DE 197 14 605 A1 to Volle, U.S. Pat. No. 4,336,870 to Shea, U.S. Pat. No. 4,635,772 to Gadelius and WO 2006/082191 to Tegtmeyer.
In applications where torque transmission needs to be performed between a mobile unit moving laterally with respect to a stationary unit, or many such stationary units, the typical prior art approach is oftentimes not practicable. Specifically, when the mobile unit is a robot that moves laterally from station to station to transfer torque to machinery mounted at each station, traditional methods of torque transfer are not well suited. Under these conditions repeatable and reliable axial actuation is difficult to perform.
An exemplary teaching showing how to adapt traditional torque transfer apparatus and methods under these circumstances is found in U.S. Published Application 2012/01522877 Tadayon. Among many aspects, this reference teaches a robot for solar farms where such torque transmission to a stationary unit, e.g., a stationary unit bearing a solar tracker, is required. In one case torque transfer is accomplished by a rack and pinion mechanism. In another case the transmission of torque from the robot to the tracker is performed with the aid of a mechanism called a “tilt arm” that produces motion along the axis about which torque is to be transmitted.
In view of the above teachings new solutions to torque transfer between mobile units, e.g., robots, traveling laterally with respect to stationary units, e.g., docking stations, are needed.